Microsoft spotted an attack group distributing a malicious Excel document on a site requiring users to complete a CAPTCHA. The Excel file contains macros that, when enabled, install GraceWire, a trojan that steals sensitive information. The attacks are the work of a group Microsoft calls Chimborazo, which company researchers have been tracking since at least January. The group is now using websites with CAPTCHAs to thwart automated analysis defenders use to detect and block attacks and get attack campaigns shut down.”]